Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 33 for “"GPS signal"”.
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Weak GPS Signal Acquisition Using Antenna Diversity
… the coherent integration time. However, in weak signal situations, using only long coherent integration is limited by navigation data bit transitions and receiver oscillator instability. Using non-coherent and differentially coherent integration mitigates the bit transition problem but has lower …
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A software defined GPS signal simulator design
The Global Positioning System (GPS) signal simulator plays a critical role in developing and testing GPS receivers. Unfortunately, very few commercial GPS signal simulators are user-friendly for security researchers because they fail to generate abnormal GPS signals, which are fundamentally …
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A GPS Signal Generator Using a ROACH FPGA Board
<p>A Global Positioning System (GPS) signal simulator is a valuable testing tool. It allows for testing of GPS receivers, systems, and anti-spoofing algorithms. With the increased popularity of software defined radios (SDRs) merging GPS signal simulators and SDRs is a natural choice. A detailed …
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Development and Testing of A Space-borne GPS Signal Strength Sensor
The Global Positioning System (GPS) satellite signals provide not only traditional radionavigation service but inexpensive and convenient radio beacons for signal propagation studies on ionosphere and atmosphere. This thesis describes the development and testing of a specialized GPS sensor which …
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Implementation Of Path Planning Methods To Detect And Avoid GPS Signal Degradation In Urban Environments
… these autonomous vehicles are prone to GPS signal loss in urban environments due to obstructions that cause scintillation, multi-path, and shadowing. These effects that decrease the GPS functionality can deteriorate the accuracy of GPS positioning causing losses in signal tracking …
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Improving the robustness of GPS direct position estimation
Global Positioning System (GPS) receivers are increasingly used for positioning in urban environments and precise timing in critical infrastructures. These scenarios are challenging for GPS receivers because building reflection and obstruction contribute to GPS signal degradation in urban …
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Conformal Microstrip GPS Antenna for Missile Application
… coordinate data. The Global Positioning System (GPS) is used for this positional awareness. However, due to missile rotation and orientation variations during flight, GPS signal reception using traditional antennas may be intermittent. To remain cost competitive, Stellar Exploration Inc. is …
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Innovative Location Based Scheme for Internet Security Protocol. A proposed Location Based Scheme N-Kerberos Security Protocol Using Intelligent Logic of Believes, Particularly by Modified BAN Logic.
… user identity. Improving Kerberos protocol using GPS signal is proposed in order to eliminate the effect of replay attack. This proposal does not expect a high performance from the user during the implementation of the security system. Moreover, to give users more confidence to use security …
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Development of a Low-Cost Navigation System for Autonomous Off -Road Vehicles
… fusion algorithm can effectively bridge the signal interruption during a GPS signal outage of 30 s. The error model-based fusion algorithm can provide the signals at 50 Hz using the 1 Hz update rate of the complementary Kalman filter.
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GPS spoofing detection for the power grid network via a multi-receiver hierarchical architecture
… network using the Global Positioning System (GPS) as a common timing reference. GPS serves as an excellent timing source due to its global coverage as well as its precise, sub-microsecond level timing accuracy. However, because civilian GPS signals are unencrypted with a publicly available …
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Indoor Geo-location And Tracking Of Mobile Autonomous Robot
… co-ordinates such as latitude and longitude. GPS signal provides us sufficient and reliable data for such decision making. The main drawback of using GPS is that it is unavailable indoors and also there is signal attenuation outdoors. Indoor geolocation forms the basis of tracking robots …
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Location Based Authentication
… and thus hard to steal. However, accuracy of the GPS, signal strength inside the building, etc, affects its potential. Consequently, there is a need to address alternatives. One such alternative is to implement a puzzle-based authentication scheme based on the location information. In the proposed …
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SIGNAL ANALYSIS AND RADIOHOLOGRAPHIC METHODS FOR AIRBORNE RADIO OCCULTATIONS
Global Positioning System (GPS) radio occultation (RO) is an atmospheric sounding technique utilizing the change in propagation direction and delay of the GPS signal to measure refractivity, which provides information on temperature and humidity. The GPS-RO technique is now operational on several …
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Effects of atmospheric pressure loading on GPS measurements
… positioning capabilities, annual fluctuations in GPS height estimates can now be resolved. A likely explanation for these height variations is loading of the Earth's surface. We examine the relative contribution of atmospheric pressure loading to the total signal by modeling loads utilizing …
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Machine Learning-based GPS Jamming and Spoofing Detection
… reliance on Global Positioning System (GPS) technology across various sectors has exposed vulnerabilities to malicious attacks, particularly GPS jamming and spoofing. This thesis presents an analysis into detection and mitigation strategies for enhancing the resilience of GPS receivers …
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Partially Supervised Reinforcement Learning for GPS-Denied Navigation
… task where a drone at one time has access to GPS location information, which it has now lost and needs to navigate in the same area but at a future time with no GPS signal and differing transition dynamics. To address this, we introduce a novel simulator and algorithm for navigation that …
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Optimal estimation of ionosphere-induced group delays of global positioning satellite signals during launch, orbit and re-entry
… range error in a Global Positioning Satellite (GPS) signal that has traveled to a receiver near the earth's surface. Among these is the ionospheric group delay. In the past, a single-state, dual-frequency filter has been used to estimate the ionospheric delay for authorized users. Although …
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Positional accuracy of the Wide Area Augmentation System
… data collection in many fields. Consumer-grade GPS units without differential correction have a published horizontal accuracy of approximately 10 to 15 meters (average error). An attractive option for differential correction for these GPS units is the Wide Area Augmentation System (WAAS). Most …
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Current Ground Deformation Derived from GPS Observations near PBO Station AC 55 along the Yentna River, South of Denali National Park Reserve, Alaska
… operating Global Positioning System (GPS) stations, of which approximately 200 are located in Alaska. GPS station AC55 was accidently installed on a slow moving landslide. In order to isolate the landslide motion, this study uses 20 stations within 100 km proximity of AC55 to separate …
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Attack resilient GPS based timing for phasor measurement units using multi-receiver direct time estimation
… These PMUs depend on Global Positioning Systems (GPS) for precise time and synchronization. However, GPS civil signals are vulnerable to external attacks because of its low power and unencrypted signal structure. Therefore, there is a need for the development of attack resilient GPS time transfer …
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